When making electrically conductive vias in a wafer of some kind (i.e. semiconductor, ceramic, polymer, etc.), electro- or electroless plating is often used. In such cases, in order to do so, it is necessary to deposit a thin seed layer that will form the base for the plating metal to build up on. Typically, this involves use of photolithography including application of a photoresist to the wafer, deposition of the seed, and removal of the photoresist. Most photoresist is applied as a viscous liquid, so it is difficult to precisely control the edges of where it should/should not be present. Thus, one of the byproducts of this approach and inaccuracy is a build up of excess seed metal during deposition of the seed layer near the edges of where the photoresist was. This excess seed metal is called overburden. This overburden can cause problems and thus, in most cases, must be removed through at least one additional processing step. In addition, the lack of precision control can lead to some photoresist entering a via, particularly when high density, narrow vias are involved. Wherever this happens, there will be no seed metal deposited for the plating to build up on or the overburden can cause unwanted short circuits.
Thus, there is a need for an approach that does not cause the aforementioned problems.